Question

Why after the passage of animals from the aquatic to the terrestrial habitat does the abandonment of the ammoniotelic excretion occur?

Answer 1

Ammonia is a highly toxic molecule if not diluted and quickly excreted out of the body. For this reason the ammoniotelic excretion was abandoned in terrestrial habitats because the availability of water for dilution is reduced in this medium and wastes cannot be excreted so promptly to the exterior.